Means for releasably latching a recoiling mass against counterrecoil movement

ABSTRACT

In a large caliber gun of the type in which the firing must be completed during the counterrecoil stroke thereof, the releasable retention of the recoiling parts in a stationary position is accomplished by a latch fixed to one end of each of a pair of linkages pivotally mounted to the respective opposite sides of the stationary cradle in which the recoiling parts are slidably mounted. Each linkage is formed by a plurality of links pivoted end to end and arranged to be pivoted by a cam on the recoiling parts of the gun whereby the latches are lifted into the counterrecoil path of the parts. This pivotal actuation of the linkages is arranged to be halted with a minimum of rebound in a position in which the latches are rigidly supported thereby against the counterrecoil force of the recoiling parts and yet can be rapidly collapsed to release the parts in response to the relatively light pull of a manually operable lanyard.

United States Patent Inventors Robert J. Schulz Davenport, Iowa; Jimmy R. Williams, Bettendori, Iowa; Robert J. Seamands, Moline, Ill. Appl. No. 841,013 Filed July 11, 1969 Patented Sept. 14, 1971 Assignee The United Stats of America as represented by the Secretary oithe Army MEANS FOR RELEASABLY LATCHING A RECOILING MASS AGAINST COUNTERRECOIL MOVEMENT Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Stephen C. Bentley Attorneys-Harry M. Saragovitz, Edward J. Kelly, Herbert Berl and Albert E. Arnold, Jr.

ABSTRACT: In a large caliber gun of the type in which the firing must be completed during the counterrecoil stroke thereof, the releasable retention of the recoiling parts in a stationary position is accomplished by a latch fixed to one end of each of a pair of linkages pivotally mounted to the respective opposite sides of the stationary cradle in which the recoiling parts are slidably mounted. Each linkage is formed by a plurality of links pivoted end to end and arranged to be pivoted by a cam on the recoiling parts of the gun whereby the latches are lifted into the counterrecoil path of the parts. This pivotal actuation of the linkages is arranged to be halted with a minimum of rebound in a position in which the latches are rigidly supported thereby against the counterrecoil force of the recoiling parts and yet can be rapidly collapsed to release the parts in response to the relatively light pull of a manually operable lanyard.

MEANS FOR RELEASABLY LATCHKNG A RECOILING MASS AGAINST COUNTERRECOIL MOVEMENT The invention described herein may be manufactured, used and licensed by or for the government for governmental purposes without the payment to us of any royalty thereon.

BACKGROUND OF THE INVENTION This invention relates to large caliber guns of the type wherein the firing is accomplished during the return of the recoiling parts to the forwardmost or battery position and is more particularly directed to an improved latch means for releasably retaining the recoiling parts in a rearward stationary position.

The problem of maintaining relatively low trunnion forces in large caliber guns of the type which are arranged to be fired during the counterrecoil travel of the recoiling parts has recently been successfully solved by the use of a hydraulic firing mechanism arranged to be automatically activated when the forward travel of the recoiling parts attain a predetermined velocity dependent on such variables as the size of the propellant charge, the ammunition, the elevation of the gun, and the viscosity of the hydraulic fluid as described in the copending patent application of Messrs. Jimmy H. Williams and Lawrence L. Frauen entitled Velocity-Sensor Firing Mechanism For Artillery Weapons, Ser. No. 828,561 filed May 28, 1969 and assigned to the same assignee. During each cycle of operation of a gun with this type of firing mechanism, it is essential that the recoiling parts be latched in a stationary rearward position to permit a new round of ammunition to be loaded into the firing chamber in the gun tube.

However, in view of the relatively high forces required to accelerate the heavy recoiling parts of a large caliber gun to the predetermined forward velocity, considerable difficulty has been encountered in providing a strong and reliable latch mechanism which will positively retain these parts, hereinafter referred to as the recoiling mass, against forward movement and yet permit the rapid release thereof with a minimum of manual effort. While the required strength and rigidity can be obtained from a conventional latch of the type which is pivoted into abutment with a fixed stop so as to extend upwardly into the path of the recoiling mass, considerable effort is required to release a latch of this type. This is primarily due to the fact that the location of the fixed stop requires that the latch be pivoted in a direction opposing the forward thrust of the recoiling mass thereby necessitating a slight but significant retraction thereof in order to disengage from the latch. Moreover, as the latch is pivoted to disengage from the recoiling mass, the continuous decrease in the area of the contact surface therebetween produces a corresponding increase in the unit stress on such surface which results in excessive wear thereof.

Another problem involved in latching the relatively heavy recoiling mass of the aforesaid type of a large caliber gun in a stationary rearward position is the necessity for resetting the latch mechanism within the extremely limited time frame available during the overtravel of the recoiling mass beyond the latching point. In fact, if the firing of a round does not provide the expected recoil forces, the overtravel of the recoiling mass is even further reduced thereby requiring an extremely rapid functioning of the means for actuating the latch mechanism to reengage with the recoiling mass. In the event the latch mechanism includes a plurality of linked components movable into and out of contact with fixed stops, any rapid change in the position of these components would result in undesirable bouncing thereof which could adversely affect the required positiveness of the latching function. Furthermore, in view of the likelihood that the lanyard may still be in the pulled position thereof at the time the recoiling mass passes the latching point, it is essential that the resetting of the latch mechanism be automatically carried out independently of the operation of the lanyard connected thereto.

Accordingly, it is a primary object of this invention to provide an improved latch means for positively retaining the relatively heavy recoiling mass of a large caliber gun in a stationary rearward position.

It is a further object of this invention to provide latch means, as aforesaid, of sufficient strength and reliability to securely retain the recoiling mass against forward movement and yet permit an immediate and rapid release thereof in response to the relatively light pull of a conventional lanyard.

Another object of the present invention is to provide a releasable latch means, as aforesaid, which can be automatically reset with great rapidity and with a minimum of rebound during the recoil travel of the recoiling mass beyond the latching point.

An additional object of this invention lies in the provision of a latch means, as aforesaid, wherein the required automatic resetting thereof is isolated from the pull of the lanyard utilized to disengage the latch means from the recoiling mass.

Still another object of this invention is to provide latch means, as aforesaid, wherein the resetting operation thereof can be accomplished with much less force than that required in latches arranged to pivot against the parts being retained thereby.

A further object of the present invention is the provision of latch means, as aforesaid, which will positively and reliably retain the recoiling mass of a large caliber gun against the high forces required to accelerate the mass to the firing position regardless of the angle of elevation at which the gun is oriented.

SUMMARY OF THE INVENTION It has been found that these objects can best be attained by a latch mechanism consisting essentially of a linkage mounted to the exterior of each of the sidewalls of the U-shaped cradle in which the recoiling mass is slidably supported for recoil and counterrecoil movement. Each linkage includes a trio of links pivotally mounted to one another in a generally vertical endto-end relation. A rotatable shaft extending transversely through the cradle connects the lowermost links of each trio so that movement of one linkage is simultaneously transferred to the other. The upper link in each trio is fixedly secured to one end of a rotatable axle transversely seated in each sidewall of the U-shaped cradle at a location rearward of the shaft connecting the linkages. As these axles are rotated by the actuation of each linkage between a rigid upright position and a pivoted collapsed position, a latch fixed to the opposite end of each axle is moved into and out of the path of the forward travel of the recoiling mass.

The length of each upper link is such that when pivoted to the horizontal position required to dispose the latches in the forward path of the recoiling mass, the pivotal connections between the upper and intermediate links and between the intermediate and lower links are both arranged to lie in vertical alignment with the center of rotation of the transverse shaft. In this position of the linkages, the intermediate and lower links in each trio are oriented to withstand the relatively high compressive forces imparted thereto by the upper link in response to the forward force of the recoiling mass against the latches.

In order to free the recoiling mass for continuation of the forward counterrecoil movement thereof, a lanyard is mounted to the right-hand sidewall of the cradle so that any pull thereon exerts a horizontal force on the pivotal connection between the intermediate and lower links. Once the rigidity of this pivotal connection is overcome by the lanyard pull, the forward force of the recoiling mass against the latches is transmitted to the links to continue the pivotal collapse thereof at a faster rate than the continued pull on the lanyard. Thus, while the orientation of the links will resist any collapse thereof under the extremely high forward force of the recoiling mass, the initiation of such collapse can be readily accomplished with a relatively light pull on the lanyard.

During the relatively short period in which the latching surface on the recoiling mass is in an overtravel status relative to the latches, the linkage must be reset to position the latches in the forward path of the recoiling mass. This is accomplished by the action between a cam on the underside of the frame in which the gun tube is mounted and a follower secured to the inner end of a rotatable torsion bar unit transversely mounted in the left-hand sidewall of the cradle to extend into the U- shaped interior thereof. The opposite and outer end of the torsion bar unit is connected to the lower link of the trio so that the rotation imparted to the torsion bar unit through the pivotal movement of the cam follower is utilized to rotate the latches into the path of the recoiling mass even through the lanyard may still be held in the pulled position thereof. Inasmuch as the restoration of the linkages to the latching position thereof is abruptly halted by the contact thereof with fixed stops on the sidewalls of the cradle, the resulting rebounding of the linkages produces considerable wear on the connections between the components thereof and, in some instances, could even cause actual damage thereto. Thus, in order to counteract and dampen these rebounds, the torsion bar unit is provided with a preload to ensure that the linkage components will follow the movements imparted thereto by the action of the follower on the cam. This preload is supplemented by a tension spring stretched between the pivotal connection of the upper and intermediate links and a rearward extension on the lower link.

BRIEF DESCRIPTION OF THE DRAWINGS The exact nature of the invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawings wherein:

FIG. 1 is a perspective view of a gun in which a recoiling mass is slidably mounted in a stationary cradle and shows the portion of the latch mechanism which is attached to the left side of the cradle;

FIG. 2 is an enlarged right-hand side view of the gun showing the portion of the latch mechanism thereon in the position assumed thereby during the retention of the recoiling mass against forward movement;

FIG. 3 is an enlarged section taken along the line 3-3 in FIG. 2 to show the manner in which the linkage portion of the latch mechanism on the left side of the cradle is joined to the linkage portion on the right side thereof;

FIG. 4 is a view of the right side of the cradle taken along line 4-4 in FIG. 3 to show the relationship ofthe release lever to the pivotal joint between the lower and intermediate links, the lanyard being shown connected to the linkage prior to the release of the recoiling mass;

FIG. 5 is a section taken along line 5-5 in FIG. 3 showing the positions of the latch and the cam follower during the latching retention of the recoiling mass as viewed from the interior of the U-shaped cradle, a portion of the sidewall being additionally broken away to show the details of the linkage in full;

FIG. 6 is a perspective view of the lower link in the linkage for the righthand sidewall of he cradle;

FIG. 7 is a similar view of the lower link in the linkage for the left-hand sidewall of the cradle;

FIG. 8 is an enlarged fragmentary side view taken along line 8-8 in FIG. 3 to show the pivotal connection between the lower and the intermediate links on the right-hand side of the cradle and the relationship of the lanyard-operated release lever when the linkages are positioned to retain the recoiling mass in the latched position;

FIG, 9 is a view similar to that of FIG. 8 but showing the relationship of the links duringthe initial pivotal collapse imparted thereto by the pulling of the lanyard;

FIG. 10 is a view similar to that of FIGS. 8 and 9 but showing the relationship of the parts subsequent to that shown in FIG. 9 but prior to the termination of the collapsing movement thereof;

FIG. 11 is a side view of the linkage on the right-hand sidewall of the cradle showing the position of the links at the end of the pivotal collapse thereof and the lanyard in the pulled position thereof;

FIG. 12 is a view similar to that of FIG. 5 but showing the relationship of the linkage components in the fully collapsed position thereof immediately following the release of the recoiling mass from the latched position thereof;

FIG. 13 is a fragmentary view looking toward the left-hand sidewall of the cradle from the interior thereof and showing the cam on the underside of the gun tube frame acting on the cam follower during the overtravel of the recoiling mass beyond the latching position thereof, the sidewall being additionally broken away to show the connection between the reset lever and the actuating link in full;

FIG. 14 is a sectional view taken along line l4 14 in FIG. 5 and enlarged to show the details of the torsion bar unit and the relationship thereof to the shaft connecting both linkages; and

FIG. 15 is a side view similar to that of FIG. 4 but showing the lanyard in the pulled position thereof and the relationship of the release lever to the linkage subsequent to the return thereof to the position required to support the latch against the counterrecoil force ofthe recoiling mass.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings wherein similar reference characters have been employed to designate corresponding parts throughout, the gun for which the present invention has been designed is a relatively large caliber howitzer in which a gun tube 12 is provided with a breechblock housing 14 coupled to the breech end thereof. All reference to such terms of direction as forward, rearward," right, and left are based on the position of an observer standing at the breech end of gun tube 12 and looking toward the muzzle thereof. A cylindrical frame or sleigh 15 surrounds the breech end of gun tube suitably and is suitably bolted thereto. A longitudinal rib 16 projects from each side of frame 15 to ride in a mating track 18 formed in the corresponding sidewall 20 of the U-shaped interior of cradle 22. Thus, frame 15 serves as a carrier for gun tube 12 during the recoil and counterrecoil movements thereof which are facilitated by a roller 24 projecting from each side thereof above rib l6 and arranged to ride along the top edges of the spaced sidewalls 20 of cradle 22, A recuperator unit 26 is fixedly attached to gun tube 12 to extend thereabove in parallel relation and is provided with a quantity of nitrogen gas in the forward end thereof which is separated from a rearward volume of hydraulic fluid. Recuperator unit 26 is hydraulically connected to a recoil unit 28 (FIG. 1) consisting of a cylinder 30 filled with hydraulic fluid and coaxially secured to the underside of frame 15 in slidable engagement with a piston 32 fixed to the rear end of cradle 22 in the bottom of the U-shaped interior thereof. Thus, gun tube 12, frame 15, recuperator unit 26 and recoil cylinder 30 are combined to recoil and counterrecoil as a single mass. During the recoil travel thereof, the hydraulic fluid in recoil cylinder 30 is forced therefrom to flow into recuperator unit 26 and compress the nitrogen gas therein. Upon termination of recoil, the compressed nitrogen gas acts to reverse the flow of hydraulic fluid and produce a constantly increasing force against the forward end of recoil cylinder 30 capable of imparting forward acceleration to the recoiling mass. A firing mechanism 34 is incorporated in the rear end of recuperator unit 26 in hydraulic connection therewith as well as with recoil unit 28 and is arranged to be activated during the forward or counterrecoil travel of the recoiling mass upon the attainment thereby of a predetermined velocity.

However, in order to provide another cycle of operation, the recoiling mass must be halted in a stationary position while the breech is opened by the upward movement of a vertically slidable breechblock 36 in housing 14 to permit replacement of the fired case with a new round of ammunition. Accordingly, the present invention provides a superior latching arrangement for retaining the recoiling mass in the stationary position required to load a fresh round in gun tube 12. Such arrangement consists essentially of a linkage secured to the exterior surface of each sidewall 20 of cradle 22 and joined so that the movement imparted to one linkage is simultaneously transferred to the other.

As best shown in FIG. 3, each linkage includes an axle 38 rotatably mounted in spaced bushings 40 contained in a bearing structure 42 transversely housed in the upper portion of cradle sidewall 20. One end of each axle 38 extends into the U-shaped interior of cradle 22 and terminates in an integral lug 44 with a vertical latching surface 46 thereon arranged to be positioned into the path of the front end of longitudinal rib 16 for retaining frame and thereby the entire recoiling mass against forward movement. The opposite end of each axle 38 is'ex'tended outwardly from the bearing structure 42 to engage with a hub 48 on the rear end of lever arm 50. As shown at 52, in FIG. 4, hub 48 is keyed to axle 38 and is retained against lateral movement by a transverse pin 54. Lever arm 50 is symmetrically tapered so that the end opposite hub 48 is reduced in size to permit pivotal engagement thereof within the bifurcated end 56 of a substantially rectangular link 58. The pivotal connection between lever arm 50 and link 58 is provided by a hinge pin 60 terminating in a projecting end 62 of reduced diameter on which a washer 64 is retained by an adjacent cotter pin 66 to provide an annular groove for the attachment of one end of a tension spring 68. The lower end of each link 58 is also bifurcated, as indicated at 70, in FIG. 3, to straddle, on the right-hand side of cradle 22, the reduced end 72 of a lower link 74. The mating ends of links 58 and 74 are pivotally joined by a transverse pin 76 therethrough terminating in an enlarged head 78 at the end adjacent sidewall of cradle 22. Head 78 is rotatably seated in a corresponding counterbore formed into the side of a release lever 80. The opposite end of pin 76 is provided with a washer and cotter pin arrangement 82 which positions and retains release lever 80 in pivotal abutment with the side of link 58. As shown in FIGS. 8-10, lever 80 extends forwardly of the connection between links 58 and 74 to terminate in a transverse stud 83 encircled by an annular groove 84 arranged to receive the looped end 86 of a lanyard 88 for a purpose to be explained.

The reduced end 72 of lower link 74 includes an upwardly extending step 90 disposed rearwardly of and adjacent to the portion straddled by bifurcated end 70 of link 58. A stop pin 92 is centrally positioned on the side of step 90 to project therefrom slightly above the top of the portion of link 74 which lies within bifurcated end 70 of link 58. Release lever 80 extends rearwardly of transverse pin 76 therethrough into contact with the underside of stop pin 92 and terminates in a depending portion of triangular configuration 94 provided with a pin 96 therethrough to which one end of a tension spring 98 is suitably attached. The other end of spring 98 is suitably fastened to the exterior surface of sidewall 20 of cradle 22, as by a bolt 100 located rearwardly of link 74 in the vertical position thereof.

Link 74 is provided with a rearwardly projecting boss 102 in which a transverse pin 104 extends therefrom toward cradle sidewall 20 to provide an attachment for the lower end of tension spring 68 which is retained thereon by a washer and cotter pin arrangement 106 similar to that utilized to retain the opposite end in engagement with hinge pin 60. At the lower end thereof, link 74 terminates in a cylindrical hub 108 fixedly secured, as indicated at 1 10, in FIG. 3 in keyed engagement with the protruding end of a shaft 1 12 rotatably mounted in bearing sleeves 114 transversely fixed in each of the sidewalls 20 of cradle 22. Shaft 112 is longitudinally located in cradle 22 so that the pivot point of link 74 thereon will be in vertical alignment with the corresponding pivot point between link 58 and 50 when the latter is horizontally positioned. At

t such time, lug 44 is fully raised into the forward path of the corresponding rib 16 on frame 15 and is retained in that position by the vertical alignment of links 58 and 74. To this end, a stop 118 is fixedly secured to sidewall 20 of cradle 22 to halt link '74 in the position in which link 58 will be vertically aligned therewith.

The linkage on the left sidewall 20 of cradle 22 is essentially identical to that on the right sidewall except that the pivotal connection between the intermediate and lower links omits release lever and utilizes a transverse pin 120 which is shorter than transverse pin 76 but otherwise similar thereto. In addition, the configuration of the lower link. hereafter identified as 121 and shown in FIG. 7, is slightly different from link 74 of FIG. 6. Such difference consists of the elimination of step 90 and the shaping of the reduced upper end to terminate in an arcuate contour 122 containing a centrally located hole 123 for the reception of transverse pin 120. Also, an elongated rectangular link 124 is provided to connect the central portion of lever arm 50 to the forward end of a reset lever 125 which is, in turn, connected to a torsion bar unit 127. The rear end of lever 125 is splined, as indicated at 126 in FIG. 14, to the end of a torsion bar 128 which protrudes from the left-hand sidewall 20 of cradle 22. The opposite end of torsion bar 128 is also splined, as indicated at 130, to the corresponding end of a surrounding hollow tube 132 which is, in turn, rotatably seated between spaced bushings 134 fixed in each end of a bearing member 136 extending through left hand sidewall 20 into the U-shaped interior of cradle 22. Bearing member 136 is fixed in sidewall 20 by welding or other suitable technique and the opposite end thereof is suitably supported by a vertical plate 137 mounted in the bottom of the interior of cradle 22.

The splined end of torsion bar 128 above plate 137 is arranged to protrude from tube 132 in fixed engagement with one end of a cam follower 138 disposed in rotatable abutment with the end of hollow tube 132. The other end of tube 132 terminates in a substantially triangular arm 140 provided with a transverse stop pin 142 at the apex thereof. Since stop pin 142 is not installed in the apex of arm 140 until the latter has been rotated to position such apex above the top edge of reset lever 125, the protruding end of pin 142 contacts lever 125 to retain arm 140 in the rotated position thereof. As a result, the torsional energy imparted to torsion bar 128 by the rotation of arm 140 is retained to provide a preload thereon for a purpose to be described. Cam follower 138 terminates in an enlarged arcuate rear end 144 arranged to be contacted by a mating cam surface 146 at the rear end of a substantially rectangular ridge 148 depending from the underside of frame 15. Thus, during the overtravel of frame 15 beyond the pivot points of lugs 44, cam surface 146 on ridge 148 pivots follower 138 counterclockwise, as viewed in FIGS. 12 and 13, to impart corresponding rotation to torsion bar unit 127 which, in turn, lifts reset lever 125 to actuate lever arms 50 for returning lugs 44 into the path of ribs 16 on frame 15.

As previously described, the looped forward end 86 of lanyard 88 is rotatably connected to stud 83 at the forward end of release lever 80. The rear end of lanyard 88 is provided with a similar looped end 150 engageable with a transverse stud 152 centrally disposed on the side of a transfer lever 154 pivoted at the upper end thereof to the right-hand sidewall 20 of cradle 22. A spacer 156 between the pivotal end of lever 154 and sidewall 20 ensures sufficient clearance for the required pivotal movement of lever 154. The lower end of lever 154 includes a fixed transverse pin 158 engageable with the looped end 160 of a primary lanyard 162 slidably disposed in the track of 164 of a pulley 166 vertically retained in a bracket 168 fixedly secured to sidewall 20 of cradle 22. The other end of primary lanyard 162 is formed with a larger loop 170, as best shown in FIG. 2, to facilitate the manual grasp thereof by the operator of the gun.

Thus, when lanyard 162 is pulled outwardly relative to sidewall 20, pulley 166 transfers the direction of pull to produce a longitudinal force which is amplified by transfer lever 154 and imparted to lanyard 88 and thereby to the forward end of release lever 80. Since the pull on lanyard 88 is below the pivot point of release lever 80, the latter would tend to pivot in clockwise direction if it were not for stop pin 92.

Accordingly, release lever 80 is prevented from pivoting about transverse pin 76 as it follows the arcuate path of such pin about the center of the connection between the lower end of link 74 and shaft 112. Thus, the longitudinal axis YY through stud 83 at the forward end of lever 80 will rise relative to the original position thereof shown in FIG. 8 while the parallel axis X-X through transverse pin 76 will be correspondingly lowered. Since the pull on release lever 80 actuates transverse pin 76 rearwardly, links 58 and 74 are pivoted to collapse the rigid connection therebetween. The forward force of the recoiling mass, assisted by the bias of spring 68, continues to collapse links 58 and 74 faster than the pull of lanyard 88 until link 74 is halted by contact with a stop 172 (FIG. 2) fixed to sidewall of cradle 22. Since the collapse of the pivotal connection between links 58 and 74 overtakes the pull 'on lanyard 162, a suitable'stop 174 is fixed to the righthand sidewall 20 of cradle 22 to automatically halt the pivotal movement oflever 154.

As the collapse of the pivotal connection between links 58 and 74 moves release lever 80 in an arcuate path about the end of shaft 112, the XX axis passes through the plane of coincidence with the Y-Y axis, as shown in FIG. 9. At this point, the change in the angular orientation of lever 80 and in the position of transverse pin 76 relative to the vertical axis through bolt 100 in cradle sidewall 20 reverses the direction of the bias exerted by spring 98 on release lever 80. Thus, upon the conclusion of the pivotal movement of links 58 and 74, release lever 80 has been rotated to a vertical position with the end containing stud 83 uppermost, as best shown in FIG. 11. In this position of release lever 80, lanyard 88 contains sufficient slack to permit retention thereof in the pulled position without interfering with the return of links 58 and 74 to the original vertical alignment thereof as will be hereinafter explained.

Since the linkage on the righthand side of cradle 22 is directly connected to the corresponding linkage on the lefthand side through shaft 112, the pull of lanyard 88 results in the simultaneous and identical function of both linkages. Thus, as the collapse of the linkages pivot the respective lever arms 50 downwardly, the one on the left-hand side of cradle 22 actuates elongated link 124 to pivot reset lever 125 in the same direction for imparting corresponding rotation to torsion bar unit 127 which, in turn, rotates cam follower 138 into the longitudinal path of ridge 148 on the underside of frame 15. Since torsion bar 128 is fixed to the end of hollow tube 132 adjacent cam follower 138, the rotation of the latter is transferred to triangular arm 140 on the opposite end thereof. As a result, arm 140 is rotated in the same direction as reset lever 125 to maintain the preload therebetween.

Once link 74 contacts stop 172 on the right-hand side of cradle 22 to halt the linkages in a fully collapsed position, such position is maintained by the bias of springs 68 until the recoil movement of the recoiling mass carries breechblock housing 14 rearwardly beyond latching lugs 44. At such time, cam surface 146 on ridge 148 is brought into contact with the elevated arcuate end 144 of the cam follower 138 as best shown in FIG. 13. As cam follower 138 is pivoted downwardly thereby, the adjacent end of torsion bar 128 is correspondingly rotated therewith. However, rotation of the opposite end of torsion bar 128 will be delayed until the torsional energy accumulated in unit 127 is sufficient to pivot reset lever 125 against the combination of resistances produced by the bias of springs 68 and the frictional forces within the various pivotal connections of the linkages. Once torsion bar unit 127 has been rotated to the required extent, reset lever 125 is actuated to lift elon gated link 124 and actuate pivotal arm 50 to return links 58 and 121 into vertical alignment. As the pivotal connection between links 58 and 121 passes forwardly ofthe line of action of spring 68, the bias thereof not only ensures the continued movement of link 121 into contact with stop 118 but also serves to dampen any rebound therefrom in order to prevent premature initiation of the previously described collapsing movement of the linkages. This action is simultaneously imparted to links 58 and 74 as well. Furthermore, any rebound of the linkages at this time is also resisted by the preload created in torsion bar unit 127 through the positioning of triangular arm 140 in relation to reset lever 125.

When the pivotal connection between links 58 and 74 and between links 58 and 121 is halted in vertical alignment with the pivot points of the outer ends thereof, lever arm 50 has rotated axle 38 to lift lug 44 thereon into the forward path of the corresponding rib 16 on the side of frame 15. At the same time, the pivotal movement of lever arm 50 has actuated link 124 to pivot reset lever 125 for withdrawing cam follower 138 out of the forward path of ridge 148 on the underside of frame 15. However, in some instances, the overtravel of the recoiling mass may continue well beyond the point at which latching lugs 44 are arranged to act and consequently permit ridge 148 to move rearwardly beyond arcuate end 144 of cam follower 138. Where the overtravel of the recoiling mass is of such magnitude, it has been found that the forces involved in halting the recoil travel thereof may produce sufficient shock to cradle 22 to overcome the bias of springs 68 as well as the preload of torsion bar unit 127 and initiate the collapse of the linkages. If this condition were not corrected before the subsequent counterrecoil travel of frame 15 brings ribs 16 thereon into contact with latching lugs 44, a failure to latch would result. Accordingly, the forward end of ridge 148 on the underside of frame 15 is angularly sloped, as indicated at 176 in FIG. 13, to act on arcuate 144 of cam follower 138 during the initial counterrecoil travel of the recoiling mass and restore the linkages to the required stationary position thereof before ribs 16 contact lugs 44.

When the counterrecoil travel of the recoiling mass is halted by contact with lugs 44, the forward momentum thereof produces compressive forces in links 58 and 74 and in links 58 and 121 which act to prevent any collapse of the pivotal connections therebetween under the high loading of the heavy recoiling mass. However, since the pull of lanyard 88 is directed at right angles to these compressive forces very little effort is required to initiate the collapse of links 58 and 74. Once this is accomplished, the compressive forces in links 58 and 74 produce moment arms which serve to accelerate the collapse.

If lanyard 162 is released prior to the halting of frame 15 in the latched position thereof, the return of the pivotal connection between links 58 and 74 into vertical alignment with the pivot points at the opposite ends thereof will simultaneously return release lever into the preactuated position shown in FIG. 4. However, if lanyard 162 is still held in the pulled position at the time the forward travel of frame 15 is halted, release lever 80 will be retained in the position wherein the forward end thereof lies above the pivot point provided by transverse pin 76, as best shown in FIG. 15. Thus, upon release of lanyard 162, spring 98 will return release lever 80 to the original preactuated position of FIG. 2.

Accordingly, the present invention provides a constantly reliable latch arrangement for halting the counterrecoil of the recoiling mass and positively retaining such mass against the relatively high accelerating force being imparted thereto by the recuperator unit. An important feature of the invention resides in the fact that the linkages which provide the latching function are specifically oriented to disengage from the recoiling mass with a minimum of lanyard pull and in the same direction as the resulting forward movement of the recoiling mass. Another important benefit of the present invention is attributable to the torsion bar incorporated in the cam and follower arrangement utilized to reset the linkages to their latching position. Since the torsion bar will absorb any unusual or erratic forces which may be transmitted to the follower, the impact of the linkages against their fixed stops and the resultant rebound therefrom will be effectively minimized. In addition, the preload on the torsion bar provides relatively tight connections between the individual components of the linkages which results in reduced component wear as well as in increased rapidity of response to the forces imparted thereto.

We wish it to be understood that we do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

We claim:

1. In a gun having a stationary cradle and a gun tube slidably mounted therein for recoil and counterrecoil movement, means for releasably latching the gun tube against counterrecoil movement comprising,

a pair of linkages connected for joint movement, each linkage being pivotally mounted to one of the opposite sides of the cradle and including a trio of links pivoted to one another in end-to-end relation,

a latch fixedly secured to one end of each of said linkages,

cam means on the gun tube operative during the recoil movement thereof for pivoting said linkages to position and support said latches in the counterrecoil path of the gun tube, and

means for manually pivoting said linkages to withdraw the support imparted thereby to said latches and release the gun tube for continued counterrecoil movement.

2. The combination defined in claim l wherein the connection between said linkages comprises a rotatable shaft extending transversely through the cradle.

3. The combination defined in claim ll wherein said cam means comprises a cam fixed to the underside of the gun tube and a cam follower rotatably mounted to the cradle in linked engagement with one of said linkages.

4. The combination defined in claim 1 wherein said means for manually pivoting said linkages too release the gun tube for counterrecoil movement comprises a lanyard attached to one side of the cradle in engagement with said linkage thereon.

5. The combination defined in claim 1 including spring means for resisting rebound of said linkages at the conclusion of the actuation imparted thereto by said cam means.

6. In a gun having a stationary cradle with a substantially U- shaped interior forming opposed sidewalls, a gun tube having a frame secured to the breech end thereof, means for slidably mounting the frame between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the frame and thereby the gun tube against counterrecoil movement, said latching means comprising,

a trio of links pivoted to the exterior surface of each sidewall of the cradle, each of the links in each trio being pivoted to one another in adjacent end-to-end relationship,

a latch rotatably mounted to the interior surface of each sidewall of the cradle in fixed engagement with said trio of links pivoted thereto,

a rotatable shaft extending transversely through the cradle to connect said trios of links for joint pivotal movement,

a cam fixed to the underside of the gun tube frame,

a cam follower rotatably mounted to the interior surface of one of said sidewalls of the cradle to lie in the path of said cam for actuation thereby during the recoil movement of the gun tube frame,

means for converting the rotation of said cam follower to rotation of said latches into the counterrecoil path of the gun tube frame, each of said trios of links being simultaneously pivoted into position to support said latch thereon against the counterrecoil force of the gun tube frame, and

means for manually pivoting said trios of links to withdraw the axial support imparted thereby to said latches and permit the gun tube frame to continue the counterrecoil movement thereof.

7. The combination defined in claim 6 wherein each trio of links includes,

an upper link connected to said rotatable latch,

a lower link connected to one end of said transverse shaft,

and

an intermediate link pivotally connected to the corresponding ends of said upper and lower links.

8. The combination defined in claim 6 wherein said means converting the rotation of said cam follower to rotation of said latches comprises,

a rotatable torsion bar unit extending transversely through one sidewall of the cradle with one end in fixed engagement with said cam follower,

a reset lever fixed to the opposite end of said torsion bar unit, and

a connecting link joining said reset lever to said upper link in said trio of links pivoted to the cradle sidewall in which said torsion bar unit is mounted.

9. In a gun having a stationary cradle with a substantially U- shaped interior forming opposed sidewalls, a gun tube slidably mounted between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the gun'tube against counterrecoil movement; said latching means comprising,

a pair of articulated linkages connected for joint movement, each of said linkages being pivoted at opposite ends thereof to one of the opposite sidewalls of the cradle,

a latch fixed to the upper end of each of said linkages,

a rotatable torsion bar unit transversely seated in one of the sidewalls of the cradle,

a reset lever fixedly secured at the rear end thereof to one end of said torsion bar unit,

means for connecting said reset lever to one of said linkages,

a cam follower fixed to the other end of said torsion bar unit,

a cam secured to the underside of the gun tube in position to pivot said cam follower during recoil movement and thereby rotate said torsion bar unit to actuate said reset lever for pivoting said linkages to lift said latches thereon into the counterrecoil path of the gun tube,

means for halting said linkages in position to support said latches against the counterrecoil force of the gun tube, and

a lanyard mounted on one of the sidewalls of the cradle and connected to said linkage thereon for converting manual pull of said lanyard to pivotal withdrawal of the support given by said linkages to said latches whereby the counterrecoil force of the gun tube pivots said latches to co|- lapse said linkages independently of the pull imparted thereto by said lanyard.

10. The combination defined in claim 9 including,

first spring means provided by said torsion bar unit for damping the rebound of said linkages upon the halting of the pivotal movement imparted thereto by the interaction of said cam and said cam follower, and

second spring means connected to each of said linkages for assisting said first spring means in controlling the rebound of said linkages.

11. The combination defined in claim 9 wherein said torsion bar unit comprises,

a torsion tube rotatably seated in one of the sidewalls of the cradle to extend transversely into the U-shaped interior thereof,

a torsion bar disposed within said tube in fixed engagement therewith only at the end within the interior of said cradle, said bar projecting beyond he fixed engagement thereof with said tube to fixedly mount said cam follower and projecting beyond the opposite end of said tube to fixedly mount said reset lever,

a triangular arm on the free end of said tube disposed for rotation relative to said reset lever, and

means for retaining said arm in a partially rotated position relative to said reset lever to provide a constant preload for resisting pivotal movement of said linkages out of the position in which said latches are supported thereby.

12. In a gun having a stationary cradle with a substantially U-shaped interior forming opposed sidewalls, a gun tube slidably mounted between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the gun tube against counterrecoil movement, said latching means comprising,

a rotatable shaft extending transversely through the cradle to project outwardly of the sidewalls,

a lower link fixedly secured to each of the opposite ends of said shaft to extend upwardly therefrom for joint movement,

an upper link pivotally mounted at one end thereof to each of the opposite sidewalls of the cradle,

an intermediate link pivotally connected to the proximate ends of said lower and upper links,

a latch fixedly connected to each of said upper links at the end in pivotal engagement with the sidewall of the cradle,

a cam fixed to the underside of the gun tube,

a cam follower rotatably mounted to one of the sidewalls of the cradle to extend into the U-shaped interior thereof in the path of said cam for actuation thereby during the recoil movement of the gun tube,

means for converting the rotatable movement of said cam follower to pivotal movement of said upper links whereby said latches thereon are rotated into the counterrecoil path of the gun tube and said lower and intermediate links are simultaneously pivoted into vertical axial alignment to support said latches against the counterrecoil force of the gun tube, and lanyard means operative on the pivotal connections between said lower and intermediate links to withdraw the support provided thereby to said latches and permit the counterrecoil movement of the gun tube to continue.

13. The combination defined in claim 12 wherein the connection between said latches and said upper links is provided by an axle rotatably mounted in each of the sidewalls of the cradle at a location above and to the rear of said transverse shaft therethrough.

14. The combination defined in claim 12 including,

a fixed stop on each cradle sidewall for halting said lower links in vertical axial alignment with said intermediate links to support said upper links against pivotal movement and thereby retain said latches thereon in position to resist the counterrecoil movement of the gun tube,

a torsion bar unit transversely seated in one of the sidewalls of the cradle to provide first spring means for damping the rebound of said lower links upon contact with said fixed stops, and

second spring means connected to said lower and intermediate links for assisting said first spring means in damping the rebound of said lower links.

15. The combination defined in claim 14 wherein each of said lower links is provided with a rearwardly extending boss, and said second spring means comprises a tension spring stretched from the pivotal connection between said intermediate and upper links to said bosses on said lower links.

16. The combination defined in claim 12 wherein one of the sidewalls of the cradle is provided with a fixed bracket and a pulley rotatably mounted in said bracket, and said lanyard means comprises,

a primary rearward portion engageable with said pulley,

a secondary forward portion connected to the pivotal connection between said lower and intermediate links, and

a lever pivotally mounted to the sidewall of the cradle for joining said primary and secondary lanyard portions whereby the pull on said primary portion is amplified during the transmittal thereof to said secondary portion.

17. The combination defined in claim 16 including,

a transverse pin for connecting each of said lower links to said adjacent intermediate links,

a release lever pivotally mounted on one of said transverse pins in engagement with said secondary portion of said lanyard,

a spring having one end thereof connected to the sidewall of the cradle and the other end thereof connected to said release lever, and means on said lower link for guiding said release lever to transmit the pull of said lanyard to said transverse pin until the counterrecoil force of the gun tube exceeds the pull of said lanyard in collapsing the pivotal connections between said lower and intermediate links whereupon said spring retains said release lever in position to permit the return of said latches into the counterrecoil path of the gun tube independently of the pull on said primary and secondary lanyard portions. 

1. In a gun having a stationary cradle and a gun tube slidably mounted therein for recoil and counterrecoil movement, means for releasably latching the gun tube against counterrecoil movement comprising, a pair of linkages connected for joint movement, each linkage being pivotally mounted to one of the opposite sides of the cradle and including a trio of links pivoted to one another in end-to-end relation, a latch fixedly secured to one end of each of said linkages, cam means on the gun tube operative during the recoil movement thereof for pivoting said linkages to position and support said latches in the counterrecoil path of the gun tube, and means for manually pivoting said linkages to withdraw the support imparted thereby to said latches and release the gun tube for continued counterrecoil movement.
 2. The combination defined in claim 1 wherein the connection between said linkages comprises a rotatable shaft extending transversely through the cradle.
 3. The combination defined in claim 1 wherein said cam means comprises a cam fixed to the underside of the gun tube and a cam follower rotatably mounted to the cradle in linked engagement with one of said linkages.
 4. The combination defined in claim 1 wherein said means for manually pivoting said linkages to release the gun tube for counterrecoil movement comprises a lanyard attached to one side of the cradle in engagement with said linkage thereon.
 5. The combination defined in claim 1 including spring means for resisting rebound of said linkages at the conclusion of the actuation imparted thereto by said cam means.
 6. In a gun having a stationary cradle with a substantially U-shaped interior forming opposed sidewalls, a gun tube having a frame secured to the breech end thereof, means for slidably mounting the frame between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the frame and thereby the gun tube against counterrecoil movement, said latching means comprising, a trio of links pivoted to the exterior surface of each sidewall of the cradle, each of the links in each trio being pivoted to one another in adjacent end-to-end relationship, a latch rotatably mounted to the interior surface of each sidewall of the cradle in fixed engagement with said trio of links pivoted thereto, a rotatable shaft extending transversely through the cradle to connect said trios of links for joint pivotal movement, a cam fixed to the underside of the gun tube frame, a cam follower rotatably mounted to the interior surface of one of said sidewalls of the cradle to lie in the path of said cam for actuation thereby during the recoil movement of the gun tube frame, means for converting the rotation of said cam follower to rotation of said latches into the counterrecoil path of the gun tube frame, each of said trios of links being simultaneously pivoted into position to support said latch thereon against the counterrecoil force of the gun tube frame, and means for manually pivoting said trios of links to withdraw the axial support imparted thereby to said latches and permit the gun tube frame to continue the counterrecoil movement thereof.
 7. The combination defined in claim 6 wherein each trio of links includes, an upper link connected to said rotatable latch, a lower link connected to one end of said transverse shaft, and an intermediate link pivotally connected to the corresponding ends of said upper and lower links.
 8. The combination defined in claim 6 wherein said means converting the rotation of said cam follower to rotation of said latches comprises, a rotatable torsion bar unit extending transversely through one sidewall of the cradle with one end in fixed engagement with said cam follower, a reset lever fixed to the opposite end of said torsion bar unit, and a connecting link joining said reset lever to said upper link in said trio of links pivoted to the cradle sidewall in which said torsion bar unit is mounted.
 9. In a gun having a stationary cradle with a substantially U-shaped interior forming opposed sidewalls, a gun tube slidably mounted between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the gun tube Against counterrecoil movement, said latching means comprising, a pair of articulated linkages connected for joint movement, each of said linkages being pivoted at opposite ends thereof to one of the opposite sidewalls of the cradle, a latch fixed to the upper end of each of said linkages, a rotatable torsion bar unit transversely seated in one of the sidewalls of the cradle, a reset lever fixedly secured at the rear end thereof to one end of said torsion bar unit, means for connecting said reset lever to one of said linkages, a cam follower fixed to the other end of said torsion bar unit, a cam secured to the underside of the gun tube in position to pivot said cam follower during recoil movement and thereby rotate said torsion bar unit to actuate said reset lever for pivoting said linkages to lift said latches thereon into the counterrecoil path of the gun tube, means for halting said linkages in position to support said latches against the counterrecoil force of the gun tube, and a lanyard mounted on one of the sidewalls of the cradle and connected to said linkage thereon for converting manual pull of said lanyard to pivotal withdrawal of the support given by said linkages to said latches whereby the counterrecoil force of the gun tube pivots said latches to collapse said linkages independently of the pull imparted thereto by said lanyard.
 10. The combination defined in claim 9 including, first spring means provided by said torsion bar unit for damping the rebound of said linkages upon the halting of the pivotal movement imparted thereto by the interaction of said cam and said cam follower, and second spring means connected to each of said linkages for assisting said first spring means in controlling the rebound of said linkages.
 11. The combination defined in claim 9 wherein said torsion bar unit comprises, a torsion tube rotatably seated in one of the sidewalls of the cradle to extend transversely into the U-shaped interior thereof, a torsion bar disposed within said tube in fixed engagement therewith only at the end within the interior of said cradle, said bar projecting beyond the fixed engagement thereof with said tube to fixedly mount said cam follower and projecting beyond the opposite end of said tube to fixedly mount said reset lever, a triangular arm on the free end of said tube disposed for rotation relative to said reset lever, and means for retaining said arm in a partially rotated position relative to said reset lever to provide a constant preload for resisting pivotal movement of said linkages out of the position in which said latches are supported thereby.
 12. In a gun having a stationary cradle with a substantially U-shaped interior forming opposed sidewalls, a gun tube slidably mounted between the sidewalls of the cradle for recoil and counterrecoil movement, and means for releasably latching the gun tube against counterrecoil movement, said latching means comprising, a rotatable shaft extending transversely through the cradle to project outwardly of the sidewalls, a lower link fixedly secured to each of the opposite ends of said shaft to extend upwardly therefrom for joint movement, an upper link pivotally mounted at one end thereof to each of the opposite sidewalls of the cradle, an intermediate link pivotally connected to the proximate ends of said lower and upper links, a latch fixedly connected to each of said upper links at the end in pivotal engagement with the sidewall of the cradle, a cam fixed to the underside of the gun tube, a cam follower rotatably mounted to one of the sidewalls of the cradle to extend into the U-shaped interior thereof in the path of said cam for actuation thereby during the recoil movement of the gun tube, means for converting the rotatable movement of said cam follower to pivotal movement of said upper links whereby said latches thereon are rotated into the counterrecoil path of the gun tube and said Lower and intermediate links are simultaneously pivoted into vertical axial alignment to support said latches against the counterrecoil force of the gun tube, and lanyard means operative on the pivotal connections between said lower and intermediate links to withdraw the support provided thereby to said latches and permit the counterrecoil movement of the gun tube to continue.
 13. The combination defined in claim 12 wherein the connection between said latches and said upper links is provided by an axle rotatably mounted in each of the sidewalls of the cradle at a location above and to the rear of said transverse shaft therethrough.
 14. The combination defined in claim 12 including, a fixed stop on each cradle sidewall for halting said lower links in vertical axial alignment with said intermediate links to support said upper links against pivotal movement and thereby retain said latches thereon in position to resist the counterrecoil movement of the gun tube, a torsion bar unit transversely seated in one of the sidewalls of the cradle to provide first spring means for damping the rebound of said lower links upon contact with said fixed stops, and second spring means connected to said lower and intermediate links for assisting said first spring means in damping the rebound of said lower links.
 15. The combination defined in claim 14 wherein each of said lower links is provided with a rearwardly extending boss, and said second spring means comprises a tension spring stretched from the pivotal connection between said intermediate and upper links to said bosses on said lower links.
 16. The combination defined in claim 12 wherein one of the sidewalls of the cradle is provided with a fixed bracket and a pulley rotatably mounted in said bracket, and said lanyard means comprises, a primary rearward portion engageable with said pulley, a secondary forward portion connected to the pivotal connection between said lower and intermediate links, and a lever pivotally mounted to the sidewall of the cradle for joining said primary and secondary lanyard portions whereby the pull on said primary portion is amplified during the transmittal thereof to said secondary portion.
 17. The combination defined in claim 16 including, a transverse pin for connecting each of said lower links to said adjacent intermediate links, a release lever pivotally mounted on one of said transverse pins in engagement with said secondary portion of said lanyard, a spring having one end thereof connected to the sidewall of the cradle and the other end thereof connected to said release lever, and means on said lower link for guiding said release lever to transmit the pull of said lanyard to said transverse pin until the counterrecoil force of the gun tube exceeds the pull of said lanyard in collapsing the pivotal connections between said lower and intermediate links whereupon said spring retains said release lever in position to permit the return of said latches into the counterrecoil path of the gun tube independently of the pull on said primary and secondary lanyard portions. 